Add ability to log security-related events.
Filter empty strings from the remoteAddressChain
Ensure 'uid' is present on all relevant security events.
sketch of asserting logs in tests
Move log-testing dependencies into devDependencies
Add tests for security-event logging output.
Add comment re: filtering of XFF header.
Merge pull request #453 from mozilla/rfk/security-events

Add ability to log security-related events.